Hi Ankur,
The base clock on the 6556 is 200MHz, which means it can output a sample every 5 ns. To generate a 10 ns pulse, you simply need to run it at full rate and generate "1001" or "0110". We have other HSDIO products that can achieve 200 MHz, such as the 6548, and FlexRIO Adapter Modules like the 6583.
Kyle A.
National Instruments
Senior Applications Engineer